1. Field of the Invention
The present invention relates generally to the field of mass spectrometers and, more specifically, to mass spectrometers that include electronic control circuits for generating and adjusting electronic signals.
2. Description of the Related Art
A particular type of mass spectrometers, an ion trap, includes electrodes for analysis and subsequent detection and measurement of ions having various mass-to-charge ratios. The components of ion traps typically include two grounded end-cap electrodes sandwiching a ring electrode to which a radio frequency (RF) signal is applied for the trapping of ions, a filament and repeller for producing an electron beam, lens elements for ion focusing in order to transport ions or electrons, and an electron multiplier, channel plate, or other ion detector. Each of these components must be supplied with a highly precise direct current (DC), RF signal, or other waveform in order to perform the steps required for mass analysis of a chemical sample.
There are many steps that are required to perform mass analysis of a sample. The sample must be acquired, transported to a mass spectrometer inlet, ionized, transported from the ionization region into the analyzer, mass analyzed, detected, digitized, and presented. Many of these steps require the precise generation of electronic signals which are also precisely biased and/or amplified to drive the above listed components of the mass spectrometer. For example, during and after ionization, the sample is manipulated with electric or magnetic fields or through fluid dynamics. The efficiency and accuracy of each of the analysis steps is dictated at least in part by the stability of the components that generate the electronic signals and resulting fields or flows. For the case of electronic field ion manipulation, the potential, frequency, and phase of signals driving the lens elements all can affect the motion of ions. Practical limitations to the electronic components used to generate the signals may cause enough inherent instability, imprecision, and degradation over time to affect the performance of the mass analysis.
Typically, the user monitors the quality of the data and modifies the generated signals of the mass spectrometer in order to maintain optimum performance. However, signal calibration before analysis and periodic monitoring of the quality of the data may not allow the required precision and stability of the signals to be maintained. Additionally, a user may not detect component degradation over time that is suggestive of an impending failure of the component.
What is needed in the art is a mass spectrometer that provides the required precision and stability of the signals. What is also needed in the art is a mass spectrometer that detects component degradation.